1. Field of the Invention
The present invention relates to a valve operating control system for an engine, including a first valve-operating characteristic changing mechanism adapted to change the valve lift, and a second valve-operating characteristic changing mechanism adapted to change the valve timing.
2. Description of the Related Art
There is a conventionally known a valve operating control system for an engine, which includes a valve-operating characteristic changing mechanism provided between a camshaft and a sprocket for driving the camshaft, so that the phase of the sprocket relative to the camshaft is changed in accordance with the operational state of the engine to change the valve timing. There is also such a valve operating control system known from Japanese Patent Application Laid-open No. 10-89024, in which an oil filter is disposed in an oil passage for supplying a working oil to the valve-operating characteristic changing mechanism.
In an engine including, in addition to a valve-operating characteristic changing mechanism of the above-described type adapted to change the valve timing, another valve-operating characteristic changing mechanism adapted to change the valve lift, if the positional relationship of an oil filter of the former valve-operating characteristic changing mechanism to a hydraulic pressure control valve for controlling the latter valve-operating characteristic changing mechanism is not taken into consideration, it is difficult to secure a mounting space of the oil filter, but also there is arisen a problem that the size of the engine is increased in order to engine such a mounting space. In addition, a timing chain for driving a camshaft is disposed on an end face of the cylinder head, and for this reason, it is necessary to take a measure for preventing the hydraulic pressure control valve and the oil filter from interfering with the timing chain.
Accordingly, it is an object of the present invention to ensure that the hydraulic pressure control valve for the valve-operating characteristic changing mechanism adapted to change the valve lift and the oil filer of the valve-operating characteristic changing mechanism adapted to change the valve timing are disposed rationally.
To achieve the above object, according to a first aspect and feature of the present invention, there is provided a valve operating control system for engine, comprising a first valve-operating characteristic changing mechanism adapted to change the valve lift, and a second valve-operating characteristic changing mechanism adapted to change the valve timing, wherein a hydraulic pressure control valve for controlling the first valve-operating characteristic changing mechanism and an oil filter mounted in an oil passage leading to the second valve-operating characteristic changing mechanism are mounted respectively on one side and the other side of a cylinder head at locations outside a loop of an endless transmitting belt for driving a camshaft.
With the above arrangement, the hydraulic pressure control valve for the first valve-operating characteristic changing mechanism is mounted on one side of the cylinder head at the location outside the loop of the endless transmitting belt, and the oil filter for the second valve-operating characteristic changing mechanism is mounted on the other side of the cylinder head. Therefore, the hydraulic pressure control valve and the oil filter can be disposed without interference with the endless transmitting belt and without interference with each other, thereby contributing to the compactness of the engine.
According to a second aspect and feature of the present invention, in addition to the first feature, the hydraulic pressure control valve and the oil filter are mounted outside a cover covering the endless transmitting belt.
With the above arrangement, the hydraulic pressure control valve and the oil filter are mounted outside the cover covering the endless transmitting belt. Therefore, the hydraulic pressure control valve and the oil filter can be removed without removal of the cover, leading to an enhanced maintenance, but also it is not necessary to provide an opening in the cover for mounting and removal of the hydraulic pressure control valve and the oil filter, whereby the structure of the cover is simplified.
According to a third aspect and feature of the present invention, in addition to the first or second feature, a mounted portion of the hydraulic pressure control valve and a mounted portion of the oil filter are connected to each other by reinforcing ribs and a mounting seat for the hydraulic pressure control valve for the second valve-operating characteristic changing mechanism mounted in the cylinder head.
With the above arrangement, the a mounted portion of the hydraulic pressure control valve for the first valve-operating characteristic changing mechanism and the mounted portion of the oil filter for the second valve-operating characteristic changing mechanism are connected to each other by the reinforcing ribs and the mounting seat for the hydraulic pressure control valve for the second valve-operating characteristic changing mechanism. Therefore, it is possible to enhance the rigidity of the cylinder head to which the hydraulic pressure control valve and the oil filter for the first and second valve-operating characteristic changing mechanisms are mounted.
According to a fourth aspect and feature of the present invention, in addition to any of the first to third features, the second valve-operating characteristic changing mechanism and the oil filter are mounted on the same side of the cylinder head.
With the above arrangement, the second valve-operating characteristic changing mechanism and the oil filter are mounted on the same side of the cylinder head and hence, the length of an oil passage connecting the second valve-operating characteristic changing mechanism and the oil filter to each other can be suppressed to the minimum.
According to a fifth aspect and feature of the present invention, in addition to the first feature, a mounting seat for the hydraulic pressure control valve for the second valve-operating characteristic changing mechanism is provided on an end face of the cylinder head sandwiched between a mounted portion of the hydraulic pressure control valve for the first valve-operating characteristic changing mechanism and a mounted portion of the oil filter.
With the above arrangement, the mounting seat for the hydraulic pressure control valve for the second valve-operating characteristic changing mechanism is provided on the end face of the cylinder head sandwiched between the mounted portion of the hydraulic pressure control valve for the first valve-operating characteristic changing mechanism and the mounted portion of the oil filter. Therefore, it is possible to prevent the hydraulic pressure control valve for the second valve-operating characteristic changing mechanism from interfering with the hydraulic pressure control valve for the first valve-operating characteristic changing mechanism and the oil filter, thereby providing the further compactness of the engine.
According to a sixth aspect and feature of the present invention, in addition to the fifth feature, the mounting seat for the hydraulic pressure control valve for the second valve-operating characteristic changing mechanism and the mounted portion of the hydraulic pressure control valve for the first valve-operating characteristic changing mechanism are connected to each other by reinforcing ribs.
With the above arrangement, the mounting seat for the hydraulic pressure control valve for the second valve-operating characteristic changing mechanism and the mounted portion of the hydraulic pressure control valve for the first valve-operating characteristic changing mechanism are connected to each other by the reinforcing ribs. Therefore, it is possible to enhance the rigidity of the cylinder head to which the hydraulic pressure control valves for the first and second valve-operating characteristic changing mechanisms are mounted.
According to a seventh aspect and feature of the present invention, in addition to the fifth feature, the mounting seat for the hydraulic pressure control valve and the mounted portion of the oil filter for the second valve-operating characteristic changing mechanism are connected to each other by reinforcing ribs.
With the above arrangement, the mounting seat for the hydraulic pressure control valve and the mounted portion of the oil filter for the second valve-operating characteristic changing mechanism are connected to each other by reinforcing ribs. Therefore, it is possible to enhance the rigidity of the cylinder head to which the hydraulic pressure control valve and the oil filter for the second valve-operating characteristic changing mechanism are mounted.
According to an eighth aspect and feature of the present invention, in addition to the fifth feature, the mounting seat for the hydraulic pressure control valve for the second valve-operating characteristic changing mechanism is connected to the mounted portion of the hydraulic pressure control valve for the first valve-operating characteristic changing mechanism and the mounted portion of the oil filter by reinforcing ribs.
With the above arrangement, the mounting seat for the hydraulic pressure control valve for the second valve-operating characteristic changing mechanism is connected to the mounted portion of the hydraulic pressure control valve for the first valve-operating characteristic changing mechanism and the oil filter by the reinforcing ribs. Therefore, it is possible to enhance the rigidity of the cylinder head to which the hydraulic pressure control valves for the first and second valve-operating characteristic changing mechanisms and the oil filter are mounted.
According to a ninth aspect and feature of the present invention, in addition to the first feature, a mounted portion of the oil filter protrudes from the side of the cylinder head.
With the above arrangement, the mounted portion of the oil filter protrudes from the side of the cylinder head and hence, the rigidity of the cylinder head can be enhanced.
According to a tenth aspect and feature of the present invention, in addition to the ninth feature, the mounted portion of the oil filter protruding from the side of the cylinder head is box-shaped.
With the above arrangement, the mounted portion of the oil filter protruding from the side of the cylinder head is box-shaped and hence, the rigidity of the cylinder head can be enhanced effectively.
According to an eleventh aspect and feature of the present invention, in addition to the first feature, a guide for the endless transmitting belt is fixed to a mounted portion of the oil filter.
With the above arrangement, the guide for the endless transmitting belt is fixed to the mounted portion of the oil filter and hence, the mounting rigidity of the guide for the endless transmitting belt can be enhanced.
According to a twelfth aspect and feature of the present invention, in addition to the first feature, a cover for the endless transmitting belt is fixed to a mounted portion of the oil filter.
With the above arrangement, the cover for the endless transmitting belt is fixed to the mounted portion of the oil filter and hence, the mounting rigidity of the cover for the endless transmitting belt can be enhanced.
According to a thirteenth aspect and feature of the present invention, in addition to the first feature, the filter housing of the oil filter is formed of a flat member.
With the above arrangement, the filter housing of the oil filter is formed of a flat member. Therefore, the filter housing is easy to form and is compact, as compared with a general cylindrical filter housing.
According to a fourteenth aspect and feature of the present invention, in addition to the first feature, an inlet chamber and an outlet chamber for the oil are defined within the filter housing of the oil filter coupled to the cylinder head, and a common twin ring-shaped seal member for sealing the inlet chamber and the outlet chamber is disposed on the coupled surface of the filter housing to the cylinder head.
With the above arrangement, the oil inlet and outlet chambers defined within the filter housing are sealed by the common twin ring-shaped seal member disposed on the coupled surface of the filter housing to the cylinder head. Therefore, it is possible to reduce the number of parts, as compared with a case where the inlet and outlet chambers are sealed by separate seal members.
According to a fifteenth aspect and feature of the present invention, in addition to the fourteenth feature, the outlet chamber is defined in the vicinity of bolt bores for fixing the filter housing to the cylinder head.
With the above arrangement, the outlet chamber is defined in the vicinity of a bolt bore for fixing the filter housing to the cylinder head and hence, a fastening force of a bolt passed through the bolt bore can be applied effectively to a portion near the outlet chamber, to thereby enhance the sealability.
According to a sixteenth aspect and feature of the present invention, in addition to the first feature, the filter housing of the oil filter coupled to the cylinder head is disposed to close an oil passage opening into an end face of the cylinder head and leading to the oil filter.
With the above arrangement, the oil passage opening into an end face of the cylinder head and leading to the oil filter is closed by the filter housing coupled to the cylinder head and hence, a member such as a blind plug for closing the oil passage is not required, leading to a reduced number of parts.
Each of an intake camshaft 12 and an exhaust camshaft 13 in an embodiment corresponds to the camshaft of the present invention; a timing chain 17 in the embodiment corresponds to the endless transmitting belt of the present invention; a chain guide 41 in the embodiment corresponds to the guide of the present invention; a chain cover 111 in the embodiment corresponds to the cover of the present invention; a first hydraulic pressure control valve 34 in the embodiment corresponds to the hydraulic pressure control valve for the first valve-operating characteristic changing mechanism of the present invention; and a second hydraulic pressure control valve 47 in the embodiment corresponds to the hydraulic pressure control valve for the second valve-operating characteristic changing mechanism of the present invention.
The above and other objects, features and advantages of the invention will become apparent from the following description of the preferred embodiment taken in conjunction with the accompanying drawings.